The six jurors currently working to decide whether the shooting death of 17-year-old Trayvon Martin is a crime have three options to choose from: Zimmerman can be guilty of second-degree murder, guilty of manslaughter, or not guilty.

But their verdict must be unanimous, so if all six can't agree, the trial could end with a hung jury.

"Hung jury is not a verdict. A hung jury is a mistrial," says Orlando defense attorney Lyle Mazin. "If the jury hangs the judge will declare a mistrial. "

If a mistrial is declared, the state can retry Zimmerman, Mazin said.

"Zimmerman would start right back at square one," Mazin said. "It would be as if the original trial never happened and a new jury would be selected. All of the evidence and testimony would be re-presented to a new jury."

"Of course, this would not happen immediately, the judge would set the case off for a date in the future," Mazin said.

But Circuit Judge Debra Nelson won't let the jury hang without a fight.

Typically, when a jury tells a judge after substantial deliberations that they can't reach a verdict, the judge reads what's known as an "Allen Charge," essentially asking them to go back to the jury room, explain their positions to each other, and try one last time to decide the case.

"If the jury still comes back hung after they have been given an Allen Charge, the judge will declare a mistrial," Mazin said.

Correction: An earlier version of this story misstated the possible hung-jury scenarios. The jury in this case cannot acquit on second-degree murder, but hang on manslaughter.

jeweiner@tribune.com or 407-420-5171. Follow Jeff Weiner on Twitter at @JeffWeinerOS.